1. Field of the Invention
The present invention relates to an apparatus for drying plural sheets of wet substrates such as semiconductor wafers.
2. Description of the Related Art
In the course of manufacturing semiconductor devices, there has been widely used the cleaning system wherein semiconductor wafers, LCD glass substrates and others are dried while successively immersing them in those process vessels in which either cleaning or rinsing solution is contained.
The cleaning system of this type uses the substrate drying apparatus in which the vapor of IPA (isopropyl alcohol), for example, is applied to those matters such as semiconductor wafers, which must be dried, to remove water content from them so as to dry them.
In the case of this conventional substrate drying apparatus, the drying of semiconductor wafers, for example, is usually carried out in such a way that IPA, for example, contained in the process vessel is heated into vapor, that the IPA vapor is condensed on surfaces of semiconductor wafers located above the process vessel to remove water content from them and that they are taken out into the atmosphere to evaporate the IPA.
Japanese Patent Disclosure She 63-160231 discloses a substrate drying apparatus wherein a space (or drying section) in which semiconductor wafers, for example, can be housed is provided above the vapor-processing section in which IPA vapor is applied to semiconductor wafers. In the case of this substrate drying apparatus, wafers are located in the drying section to dry IPA which has adhered to wafers. Dusts and particles are thus prevented from adhering to those wafers which are being dried.
In the case of this substrate drying apparatus, a cooling mechanism is also provided between the IPA-vapor applying section and the drying section to cool and condense IPA vapor. A dry gas supply mechanism is also provided to jet dry gas through side walls of the apparatus which are located between the vapor-processing section and the drying section. The dry gas flow thus created and the cooling mechanism cooperate to prevent IPA vapor, for example, from rising from the vapor-processing section and entering into the drying section.
In the case of the above-described conventional substrate drying apparatus, however, dry gas is jetted through side walls of the apparatus between the vapor-processing section and the drying section. IPA vapor in the vapor-processing section is thus raised up by the flow of dry gas and enters into the drying section to delay the drying of semiconductor wafers, for example, in it and to be leaked outside the apparatus.